What is 20kg x 9.8m/s2

What happens in a global convection cell

While standing outdoors one evening, you are exposed to the following four types of electromagnetic radiation: yellow light from a sodium street lamp, radio waves from an am radio station, radio waves from an fm radio station, and microwaves from an antenna of a communications system. rank these type of waves in terms of increasing photon energy.

What is the coefficient of kinetic friction μk between the block and the tabletop?